Lethal link

An expert on toxicology and a campaigner deeply concerned with the health impact of chemical pesticides, Romeo F Quijano was at the forefront of getting a ban imposed on endosulfan -- a hazardous organochlorine pesticide widely used all over the world -- in the Philippines. At present, Quijano is technical consultant to the department of agriculture as well as the department of health in the Philippines. Quijano recently visited Kasaragod district in Kerala to investigate the health damages caused by the aerial spraying of endosulfan in the cashew plantations in the state. C Surendranath travelled with him to gather his views on issues related to pesticides and health. Excerpts from an interview with Quijano

Published: Friday 15 March 2002

What is the general understanding of the term 'pesticides'?
In the Asian and South Asian countries, people often term pesticides as 'medicines'. I have heard this in the Philippines, Indonesia, Thailand and India. This is a wrong notion that the pesticide manufacturers have succeeded in implanting in the minds of the people. I have an acronym for pesticides: 'Poisons, Exterminating Species, Terminating Interdependency of Creatures and Irreversibly Destroying Earth.' For those who push these pesticides, insects are 'pests'. But for the naturalists and those who practice environmentally sustainable agriculture, insects form a necessary element in the balance of the natural system.

Can you briefly trace the history of pesticides?
It is noteworthy that the market explosion of chemical pesticides came only after the World War II. The companies then started looking out for new uses and users of their war chemicals. Till then, many Asian societies were producing food satisfactorily, in adequate amounts, without using chemical pesticides. But after the War, the developed countries told us that we needed chemical pesticides to improve agricultural production. They also came out with institutions such as the International Rice Research Institute and the so-called high-yielding 'miracle' seeds. These things came as a package.

But even Food and Agriculture Organization (fao) studies have now shown that the small farming systems of Asian countries were often more efficient than the monoculture farms produced by the Western culture. Nevertheless, even today in the Philippines, those who practise sustainable agriculture can't get their crops insured if they don't use the chemical inputs or high yielding variety seeds.

What were the reasons for widespread acceptance of pesticides?
Many of the pesticides were pushed into the markets in the 1960s and 1970s when the regulatory system to screen them for harmful effects had not developed. Everywhere the studies came much later. By then there was already a vested interest to defend the chemicals. Most often the studies were designed, done or sponsored by the manufacturer companies themselves. For instance, many studies commissioned by the pharma major Hoechst in 1983 were found to be carried out by Industrial Biotest (ibt) of Chicago, which was later convicted of fraudulent practices, including fabrication of data. Even in 1990s Hoechst was submitting ibt data to the Philippines authorities.

Despite a strong case against pesticides, countries still shy of imposing a ban. Why?
Countries began to ban one pesticide after another only when complaints from the people and scientific data began to pile up. Unfortunately, under the present system, the burden of proof is on the victims; the polluter is not required to prove that the product is safe. In the us, until 1996, they had the Delaney Clause, under which you didn't have to prove the carcinogenicity of a chemical in human beings. It was enough to prove the carcinogenicity of a chemical at the animal level to ban its use in human food. This clause has been lifted recently.

With the enforcement of the World Trade Organisation (wto) and its phytosanitary and sanitary provisions under which protection of environment is subordinate to trade interests, even state regulatory authorities are now finding it extremely difficult to ban pesticides. If a country wants to ban a chemical, it has to provide its own proof that the chemical is harmful. The us banned lindane but when Canada wanted to ban the same, the company sued the Canadian government using the provisions in the wto.

Can pesticides be considered the sole cause of most diseases today?
Looking at some of the diseases associated with pesticides and the organs affected by them, one can say that practically all of these can be caused by pesticides. I say, "can be" because there can be other causes too for these diseases; the impact of pesticides is just one among the many causes of diseases. But, then, we should also recognise that there is no single disease that has a single causative factor. This is true even of infectious diseases such as tb, aids or several sexually transmitted diseases. It is not a bacterium or a virus alone that acts as the single cause of the disease.

How is this cause and effect relationship viewed in modern medicine?
Because of the prominence of the reductionist paradigm of science and the permeation of western system of medicine, it is difficult now to recognise the interrelationship between various factors. In medicine, the dominant practice is to use a single active ingredient, a single chemical, to treat a disease. This narrow paradigm which searches for a one to one correspondence between cause and effect is not only inadequate, but also contrary to the health care systems and values of most Asian societies.

Such a paradigm largely ignores the broad inter-relationships of the ecosystem. It also ignores the infinitesimal uncertainty factors that often preclude the demonstration of cause and effect relationship and the probabilistic characterisation of risks.

How is the concept of health understood today?
Even the World Health Organisation (who) recognises the holistic nature of health when it defines it as not just absence of disease, but the complete physical, mental and social well-being of individuals. I would define health as the maintenance of the balance between the individual and all elements of his/her environment -- the physical, biological, chemical, spiritual and, perhaps the most fundamental element, the social environment. Any destruction of the balance between these elements would lead to ill health. Such a view is shared in many diverse cultures of Asia and in systems of alternative medicine.

Is it right to implicate pesticides in cancer?
Very often you hear people saying that there is no proof to say that pesticides cause cancer in human beings. Even when you show scientific evidence that pesticides have caused cancer in lab animals the comment is this: "Well this is in animals; show me the proof in humans." Truly, it is almost impossible to show a cause and effect relationship between a particular chemical and cancer in human beings.

Firstly, it takes a long time, 20-30 years, for cancer to manifest. Linking an incident of exposure or a series of exposures with the disease would be extremely difficult. Secondly, almost always there are multiple exposures to a multitude of chemicals and, not even chemicals, for that matter: uv light, radiation, certain virus etc. can lead to cancer. These are confounding variables that have to be taken into reckoning. It's extremely difficult to pinpoint a single factor. Nevertheless, there is sufficient evidence to show that several pesticides can cause cancer.

The question should not be whether certain chemical pesticides cause cancer. Rephrased scientifically, the question would be: "Does exposure to pesticides increase the risk of developing cancer and other diseases?" The categorical answer then would be: "Yes." There are several levels of evidence.

How would you substantiate this?
Firstly, several pesticides have been found to damage genes, to be genotoxic. This has been the case of several studies on endosulfan though the pesticides company has often come up with contradictory data. Then, most of the pesticides in the World Health Organisation/Environmental Protection Agency list of known carcinogens are also mutagenic, causing chromosomal mutations. So a second level of scientific evidence to show that a pesticide can be carcinogenic is to show that it is mutagenic.

A third level of evidence is at the molecular level. Several pesticides have been shown to produce effects -- for instance, estrogenic effects caused by organochlorine compounds, associated with the development of cancers. Several chemical pesticides have been shown to disrupt inter-cellular and intra-cellular communication. Again, if embryotoxicity or immunotoxicity is proved in case of a chemical, it is safe to presume that it can cause cancer, promote cancer or act as a co-promoter of cancer.

Is there any evidence at the chemical level?
Pesticides having chemical structures similar to that of known carcinogens can be safely assumed to have a similar effect. The now-banned endrin, the predecessor of endosulfan in several countries (this is true of Kasaragod district of Kerala too), has a structure quite similar to that of endosulfan. There are also evidences at the epidemiological level. If we take these different levels of evidence together to arrive at a reasonable conclusion, they are sufficient to associate pesticides with cancers and several diseases.

Without a hundred per cent proof, is there any justification in taking a precautionary action?
There may not be a direct, smoking gun evidence linking pesticides to cancer. But you don't need 100 per cent proof to protect the health of your people. With the precautionary principle, there is the recognition that long-term impacts of toxic chemicals are difficult to predict and often impossible to prove. The precautionary approach must still rely on science and on certain elements of the risk assessment methodology, to identify potential risks to human health and the environment. Yet, it does not depend on a system of decision making that demands generation of extensive scientific data and requires exhaustive analysis of risks as precondition to policy formulation and action.

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